Igniter charge for propellant compositions and rocket propellant charges

ABSTRACT

THE PRESENT DISCLOSURE RELATES TO AN IGNITER CHARGE FOR PROPELLANT POWDER CHARGES AND ROCKET PROPELLANT CHARGES COMPRISING A HOT PARTICLE IGNITER MASS CONTAINING A BINDER SELECTED FROM THE GROUP CONSISTING OF POLYEPOXIDES, POLYESTERS, POLYURETHANES, POLYBUTANDIENES, POLYOLEFINS, SILICONES, CELLULOSE DERIVATIVES, AND RUBBER, AND OXYGEN DONOR SELECTED FROMTHE GROUP CONSISTING OF AMMONIUM AND ALKALI METAL NITRATES AND PERCHLORATES AND A HOT PARTICLE DONOR SLECTED FROM THE GROUP CONSISTING OF AT LEAST ONE METAL OR METAL OXIDE OF THE ELEMENTS GROUPS I TO VIII OF THE PERIODIC TABLE.

3,682,727 IGNITER CHARGE FOR PROPELLANT COMPOSI- TIONS AND ROCKET PROPELLANT CHARGES Walter Heinzelmann, Sarninghauser, Karl-Egon Fiach, Cologne Dellbruch, Alfred Voss, Hagen, Westphalia, and Heinz Kroschel, Oberlar, Germany, assignors to Dynamit Nobel Aktiengesellschaft, Troisdorf, Germany No Drawing. Filed Aug. 5, 1969, Ser. No. 847,701 Claims priority, application Germany, Aug. 5, 1968, P 17 71 943.6 Int. Cl. C06c 9/00 U.S. Cl. 149-19 11 Claims ABSTRACT OF THE DISCLOSURE The present disclosure relates to an igniter charge for propellant powder charges and rocket propellant charges comprising a hot particle igniter mass containing a binder selected from the group consisting of polyepoxides, polyesters, polyurethanes, polybutadienes, polyolefins, silicones, cellulose derivatives, and rubber, an oxygen donor selected from the group consisting of ammonium and alkali metal nitrates and perchlorates and a hot particle donor selected from the group consisting of at least one metal or metal oxide of the elements of Groups I to VIII of the Periodic Table.

BACKGROUND OF THE INVENTION The present invention relates to igniter charges for propellant compositions and rocket propellant charges and more particularly to obviating disadvantages which substantially reduce the variations in activity and effectiveness of the igniter charge caused by the temperature dependency of the defiagrating properties of the igniter charge during the transmission of the ignition from said charge to the base propellant.

It is well known to use an igniter (booster) charge to ignite propellant powder charges for projectiles of all types, including rocket propellant charges. The igniter charge is ignited, in the case of propellant powder charges, by propellant charge primers, and in the case of rockets, by primer pellets or special primer charges. Optionally, igniting means having a more complicated construction are employed.

The igniter charge usually consists of gunpowder and/ or single-base or double-base nitrocellulose powders. However, when using such igniter charges, no uniformly effective transmission of the ignition from the igniter charge to the base propellant is achieved, due to the temperature dependency of the defiagration properties of the igniter charge within the range of use required for the respective ammunition or rocket, for example, temperatures of about 40 to +50 C. This fact also substantially increases the temperature-dependent variations of the muzzle velocity of the projectiles, or the starting acceleration of rockets, said variations being caused, on the one hand, by the temperature-dependencies of the defiagration properties of the base propellant and, on the other hand, by the mechanical properties of the cartridge material employed.

Thus, in many cases it is necessary to adjust the weapon in accordance with the respective ammunition temperature, which is cumbersome, not only in case of cartridge ammunition and rockets, but also in case of recoilless firing firarmes, for example, tank-destroying hollow-charge projectiles, with or without booster acceleration by a rocket propellant charge. Typical types of Weapons include those of the conventional bazooka-type provided with a fixed-launching tube open on both ends. The projectiles are thus driven forward by means of a propellant charge accommodated in the projectile end, the shock wave of 3,62,727 Patented Aug. 8, 1972 which is supported, with tamping, against the shock wave of a simultaneously ignited propellant charge accommodated in the rear section of the fixed-launching tube.

The two propellant charges in most cases, consist of a nitrocellulose double-base powder and are customarily disposed in a common cartridge case which in turn is ignited by an igniter charge.

SUMMARY OF THE INVENTION An object of the present invention is to avoid the prior art disadvantages in the use of an igniter charge for propellant compositions and rocket propellant charges.

Another object of the present invention is to provide an improved igniter charge composition which counteracts the temperature-dependent disadvantages and substantially reduces the variations in activity and elfectiveness caused by the temperature-dependency of the defiagrating properties of the igniter charge during the transmission of the ignition from the igniter to the propellant charge to the base propellant (powder propellant charge, rocket propellant composition, etc.).

A further object of the present invention is to reduce the associated variations in the muzzle velocity of the projectiles, or the lift-off (starting) acceleration of rockets, and consequently to achieve a more satisfactory hit distribution characteristic.

Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by Way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Pursuant to the present invention, it has been found that the above-mentioned disadvantaes may be eliminated and a much improved propellant composition may be obtained by providing a primer igniter (booster) charge for propellant powder charges and rocket propellant charges which comprises a hot-particle primer (igniter) mass containing, as a binder, a cold-curable or thermosetting polymer free of plasticizers, such as for example, polyepoxides, polyesters, polyurethanes, polybutadienes, polyolefins, silicones,

cellulose derivatives, as well as various types of rubbers. The preferred binders are polyurethanes comprising about 25 parts of a viscous, pre-polymerized diisocyanate of toluylene diisocyanate and 1,4-butanediol, said diisocyanate having an average molecular weight of about 2,000 and an average isocyanate content of about 4%. These polyurethanes are known by the trade name Adeprene L 100, which is a Du Pont product. Used in conjunction with the polyurethanes are about 2.7 parts of methylenebis-o-chloroaniline as the curing agent therefor. As the oxygen donor, ammonium or alkali metal nitrates or perchlorates, preferably potassium nitrate, can be used. The methylene-bis-o-chloroaniline, mentioned above, is known under the trade name of Moca, which is also a Du Pont product.

In this connection, the igniter charge can be made up exclusively from such a hot particle igniter mass, or it can also contain, in addition to the hot particle mass, 2. more or less large proportion of a conventional igniter powder, such as for example, gunpowder (black powder) and/or single or double-base nitrocellulose powders as well as mixtures thereof.

The igniter charge of the present invention can be employed for the ignition of gunpowders, of single or double-base nitrocellulose powders, mixtures of these with gunpowders, for the initiation of propellant powder charges in cartridge ammunition for guns and cannons, as well as for the ignition of ammunition for recoilless weapons, particularly recoilless anti-tank firearms, and rocket propellant charges of polar powders, compound powders (composite powders) and gunpowders. Additionally, however, the igniter charge is also suitable for use as a detonating charge, particularly in the ignition of cartridge ammunition and rocket propellant charges.

When the hot particle igniter mass is employed as the sole component of the igniter charge, as well as when it is being used in conjunction with a more or less large proportion of a conventional igniter powder, the igniter mass can be produced and utilized, depending on the respective application, in a more or less compressed or granulated form.

Any higher gas pressures which may occur can be lessened by reducing the total weight of the igniter charge without adversely effecting its precise functioning.

As the binder portion, the hot particle igniter mass can also contain natural cellulose, glue, starch, or gum arabic, and as the hot particle donor, the igniter mass can contain at least one metal and/r alloy or intermetallic phases of said materials. Examples of said metals and oxides can be selected from the metals of Groups I to VIII of the Periodic Table and also the transition and rare earth elements. Suitable metals and/ or metal oxides include, for example, magnesium, calcium, boron, aluminum, silicon, tin, lead, arsenic, antimony, bismuth, titanium, zirconium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, copper, zinc, cadmium, cerium, as Well as the readily reducible metallic oxides, such as for example, CuO, Cu O, PbO MnO and the like. The igniter mass preferably contains elemental boron and/or mixtures or alloys or intermetallic phases of boron with titanium, zirconium, hafnium vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, nickel, as well as other transition elements. Optionally, the hot particle igniter mass can further contain fluxes, such as, for example, calcium fluoride, magnesium oxide, as well as mold lubricants (parting compounds), such as for example, stearates or waxes.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following examples are given merely as illustrative of the present invention and accordingly are not to be considered as limiting.

Representative compositions of a gunpowder suitable for ignitions, as well as a 'suitable hot particle igniter mass are set forth in the following examples:

(a) Gunpowder for igniter charges Composition:

About 75% by weight of potassium nitrate About by weight of sulfur About by weight of charcoal (b) Hot particle igniter mass Composition:

About 24% by weight of amorphous boron About 70% by weight of anhydrous potassium nitrate About 6% by weight of a binder consisting of 90.13% by weight of Adiprene L 100 and 9.87% by weight of Moca.

The invention being thus described, it would be obvious that the same may be varied in many ways. Such variations are not to be reguarded as a departure from the spirit and scope of the invention, and all such modifications as would be apparent to one skilled in the art are intended to be included.

What is claimed is:

1. An igniter charge for propellant powder charges and rocket propellant charge comprising a hot particle igniter mass containing about 6% by weight of a binder selected from the group consisting of polyepoxides, polyesters, polyurethane, polybutadienes, polyolefins, silicones, cellulose derivatives, and rubber, about 70% by weight of an oxygen donor selected from the group consisting of alkali metal nitrates and perchlorates and a hot particle donor of elemental boron, mixtures, alloys or intermetallic phases of boron with at least one member selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, nickel and the transition elements.

2. The igniter charge of claim 1, wherein the binder is a polyurethane comprising about 25 parts of a prepolymerized toluylene diisocyanate and 1,4-butanediol having an average molecular weight of about 2,000 and an average isocyanate content of about 4%.

3. The igniter charge of claim 2, wherein the binder contains methylene-bis-o-chloroaniline as a curing agent.

4. The igniter charge of claim 3, wherein the oxygen donor is potassium nitrate.

5. The igniter charge of claim 1, further containing at least one member selected from the group consisting of nitrocellulose glue, starch and gum arabic.

6. The igniter charge of claim 1, further comprising at least one member selected from the group consisting of calcium fluoride, magnesium oxide, stearates and waxes.

7. The igniter charge of claim 1, further comprising an igniter powder.

8. The igniter charge of claim 7, wherein the igniter powder is gunpowder or nitrocellulose.

9. The igniter charge of claim 8, wherein the igniter powder is gunpower comprising about by weight potassium nitrate, about 10% by Weight sulfur and about 15 by weight charcoal.

10. The igniter charge of claim 1, comprising about 6% by weight of a binder consisting of about 90.13% by weight of a pre-polymerized diisocyanate of toluylene diisocyanate and 1,4-butanediol and 9.87% by weight of methylene-bis-o-chloroaniline, about 70% by weight of anhydrous potassium nitrate and about 24% by weight of amorphous boron.

11. An igniter charge for propellant powder charges and rocket propellant charges comprising a hot particle igniter mass containing a binder consisting essentially of about 25 parts of a viscous, pre-polymerized diisocyanate of toluylene diisocyanate and 1,4-butanediol having an average molecular weight of about 2,000 and an average isocyanate content of about 4%, about 2.7 parts of methylene-bis-o-chloroaniline as a curing agent, a hot particle donor consisting of amorphous boron and an oxygen donor selected from the group consisting of alkali metal nitrates and perchlorates.

References Cited UNITED STATES PATENTS 3,377,955 4/1968 Hodgson 149-19 3,126,305 3/1964 Armstrong 149-77 3,234,059 2/1966 Proell 149-19 3,245,849 4/1966 Klager et al. 149-19 3,257,801 l/1966 Martinez et al. 60-354- 3,350,245 10/1967 Dickinson 149-19 3,473,982 10/1969 Herzog 149-20 CARL D. QUARFORTH, Primary Examiner E. A. MILLER, Assistant Examiner US. Cl. X.R. 

